Close



Results 1 to 18 of 18
  1. #1
    FEP Power Member 306gt's Avatar
    Join Date
    Aug 2005
    Location
    Plymouth, Ma.
    Posts
    1,503

    Default 79 Pace car 2.3L turbo 4-speed conversion to T-5 Trans

    My daughter has a 79 pace car turbo 4, 4-speed and I picked up a 4 cyl T-5 Trans. I'd like to install the T-5 to bring down the revs on the highway. What do I need to do this conversion? I have a V-8 driveshaft already. Can I use the same flywheel, clutch, and bellhousing from the 4 speed and just bolt up the T-5 and use the V-8 driveshaft? I know the 4 speed is shorter then the T-5. And the driveshaft is longer when using the 4 speed. Any help will be appreciated.
    85 G.T. All motor
    337 c.i.d 11.44-120 mph

    1984 1/2 G.T. 350 (13.01-106 mph)

    1984 G.T. (Daughters car)

    1986 G.T. (Son's car) (12.99-105 mph)

  2. #2

    Default

    You should need the T5-specific bellhousing too. But if it's like a 5.0, everything else will work - though you might need to trim the shifter opening a little.
    '88 Mustang GT convertible, T5, 3.08:1 gears. 5.0 Explobra Jet: A9L Mass Air conversion, Fenderwell Mac cold air intake, 70mm MAF meter = 4.6 T-Bird/Cougar housing + '95 Mustang F2VF-12B579-A1A sensor, aftermarket 70mm throttle body and spacer, Explorer intakes, GT40P heads with Alex's Parts springs and drilled for thermactor, Crane F3ZE-6529-AB 1.7 "Cobra" roller rockers, Ford Racing P50 headers, Mac H-pipe, Magnaflow catback, Walbro 190 LPH fuel pump, UPR firewall adjuster and quadrant with Ford OEM cable, 3G conversion ('95 Mustang V6), Taurus fan, rolled on Rustoleum gloss white paint...
    Past Four Eyes: Red well optioned '82 GT 5.0, Black T-top '81 Capri Black Magic 3.3L 4 speed, Black T-top '84 Capri RS 5.0 5 speed.Over 200,000 miles driven in Four Eyes, and over 350,000 in Fox Body cars.

  3. #3

    Default

    you will need a 4 cyl T-5 bellhousing. not sure about the driveshaft. the 4 cyl T-5 has a low first gear.
    here is some good reading about the T5
    http://www.moderndriveline.com/Techn...t5_history.htm

  4. #4

  5. #5

    Default

    Could you change the gear ratio instead of the trans? I'm not sure what's in the car now, but maybe a lower number ratio would accomplish the same thing?
    Cheers!

    Mike (TopGear85)



    Have:
    85 Saleen #73-GT,2R,TuTone,Cruise,Pos,5spd,Charcoal
    ***August 2015 ROTM Winner!***

    Had:
    79PC-San Jose #2890
    86GT-9L,TuTone,5spd,T-Tops,Sand Beige
    86GT-9L,TuTone,5spd,T-Tops,Charcoal
    90LX-Oxford Wht,5spd,Sunroof,5.0 Hatchback
    90GT-Oxford Wht,5spd

  6. #6
    FEP Super Member gr79's Avatar
    Join Date
    Jun 2009
    Location
    SE Michigan
    Posts
    5,141

    Default

    Did that very same swap in 2002. 79 2.3T
    Been working fine. No issues.

    Did not remove bellhousing, clutch, clutch cable.
    Exhaust system in that area needs to be removed.
    Removed the 4 and installed the 5
    Changed the T-5 trans fluid. 3 qts DEX/Mercon ATF
    New bolts for ds flange at rear axle.
    Used strip butyl to seal lower shifter boot to tunnel.

    Four speed trans was tagged RAD
    'New' trans is 1352-209 wc T5
    41.5" driveshaft (T-5). The RAD shaft is a little too long.
    A T-5 shifter assy needs to be used of course.

    All bolted right in. One day job.
    Backup light harness connected fine and work.
    Trans mount on cross member is now all the way back in the slots. Barely made it.
    Last edited by gr79; 06-07-2015 at 12:44 PM.

  7. #7
    FEP Power Member 306gt's Avatar
    Join Date
    Aug 2005
    Location
    Plymouth, Ma.
    Posts
    1,503

    Default

    Thanks for the info. I rebuilt the trans already. I have a V-8 driveshaft and I have a T-5 shifter. I thought it was a bolt in deal using the existing bellhousing, clutch and flywheel, trans mount and crossmember. I know the T-5 is longer then the 4 -speed and therefore need a shorter driveshaft. Just trying to get my ducks in a row before the swap and to make sure there are no issues the day of the swap. If anyone can think of anything else please let me know. Thank's Paul.
    85 G.T. All motor
    337 c.i.d 11.44-120 mph

    1984 1/2 G.T. 350 (13.01-106 mph)

    1984 G.T. (Daughters car)

    1986 G.T. (Son's car) (12.99-105 mph)

  8. #8
    FEP Super Member gr79's Avatar
    Join Date
    Jun 2009
    Location
    SE Michigan
    Posts
    5,141

    Default

    Had time to casually work on the car during a three week July vacation.
    Had time to remember to dig out the trans plug.
    Garaged for a week, sitting on four jack stands.
    Trans swap and major rear brake system overhaul.

    Ideal conditions dry 95° days, 75° nights.
    Took several days. 1/2 day to locate and pick up a T5 drive shaft.
    Drove my Ranger as the parts runner.

    The handy trans jack was put into use again. This time was my car's turn.
    That tool has paid for itself several times over.

    http://vb.foureyedpride.com/attachme...7&d=1267978710

  9. #9
    FEP Power Member 306gt's Avatar
    Join Date
    Aug 2005
    Location
    Plymouth, Ma.
    Posts
    1,503

    Default

    Did you like the T-5? Does the 2.3L turbo have enuff grunt to use the O.D. 5th gear. Right now her motor at 70 mph is around 3000 rpm. She can barely keep up with traffic.
    85 G.T. All motor
    337 c.i.d 11.44-120 mph

    1984 1/2 G.T. 350 (13.01-106 mph)

    1984 G.T. (Daughters car)

    1986 G.T. (Son's car) (12.99-105 mph)

  10. #10
    FEP Super Member Travis T's Avatar
    Join Date
    Jan 2011
    Location
    China Grove, North Carolina
    Posts
    5,267

    Default

    The T5 is barely longer. As gr79 said, if you have a four cylinder T5 and your car has the RAD four speed (which your car should), the transmission itself is the only thing you need to change. I did the swap once and in my car I got away with using the factory driveshaft. I slightly modified the hole in the transmission tunnel just to bolt the shifter in. It was unbelievably easy.
    1984 Mustang GT owned since 1991 (first car). Mercury Mountaineer GT-40P engine, some suspension mods, currently undergoing a five lug SN95 brake upgrade and more suspension mods. Some minor body and interior mods have been done as well.

    2004 GT convertible, 2001 Taurus LX, 1994 F150, 1950 F-1 Ford Pickup

  11. #11
    FEP Super Member Travis T's Avatar
    Join Date
    Jan 2011
    Location
    China Grove, North Carolina
    Posts
    5,267

    Default

    Have you measured the difference in transmission length? Just curious since I didn't swap my shaft and it never bottomed out. My car was not a turbo four, just a standard, and had a 3.08 rear end. I swapped in an 86 SVO T5 and even it did fine in fifth gear. I would think yours would do well as a carbed turbo should have a 3.45 ratio.
    1984 Mustang GT owned since 1991 (first car). Mercury Mountaineer GT-40P engine, some suspension mods, currently undergoing a five lug SN95 brake upgrade and more suspension mods. Some minor body and interior mods have been done as well.

    2004 GT convertible, 2001 Taurus LX, 1994 F150, 1950 F-1 Ford Pickup

  12. #12
    FEP Super Member gr79's Avatar
    Join Date
    Jun 2009
    Location
    SE Michigan
    Posts
    5,141

    Default

    Quote Originally Posted by 306gt View Post
    Did you like the T-5? Does the 2.3L turbo have enuff grunt to use the O.D. 5th gear. Right now her motor at 70 mph is around 3000 rpm. She can barely keep up with traffic.
    The T5 stays. Have the RAD, shifter, drive shaft stored.
    T5 has many more shifter and lever options.

    Engine runs the same in the first 4 gears.
    OD drops the overall like having a 2.79 rear.
    She cruises fine on the freeway. 70 to 80 no problem.
    Hills??? Downshift. Boost takes care of mild grades.

    5th drops rpm 400.
    2000 rpm in 4th is 43 according to GPS.
    2000 rpm in 5th gives 10 more mph, 53.
    Shifting into 5th at 2000, rpm drops to 1600.
    3000 rpm in 5th is 80+

    Engine should pull smooth above say 1400 in the higher gears.
    The tough 2.3 likes higher steady rpms. 2-3 grand.

    Drove I-80 for 10 hours+ once, with the 4 speed, at steady 2800. 20+ mpg. About 60 mph.
    Detroit to NYC and back.
    Did not hurt anything one bit.

    There is no real change in mpg with the 5.
    With od, I feel a 3.73 rear would be no problem. 4.10 would still be reasonable and wild.
    Last edited by gr79; 06-09-2015 at 03:26 AM.

  13. #13
    FEP Power Member 306gt's Avatar
    Join Date
    Aug 2005
    Location
    Plymouth, Ma.
    Posts
    1,503

    Default

    Thank's guys for all of the info. I think this Sunday morning I will start the installation. I hope everything goes smooth. I'll post up the results when it is finished. Thank's again
    85 G.T. All motor
    337 c.i.d 11.44-120 mph

    1984 1/2 G.T. 350 (13.01-106 mph)

    1984 G.T. (Daughters car)

    1986 G.T. (Son's car) (12.99-105 mph)

  14. #14
    FEP Power Member 306gt's Avatar
    Join Date
    Aug 2005
    Location
    Plymouth, Ma.
    Posts
    1,503

    Default

    Well I did the swap this morning. Took a couple of hours laying on my back. The swap went smooth with no issues. This is a direct bolt-in. Everything is a direct fit I used the V-8 driveshaft and I had to change the speedometer gear over to a 20 tooth to make the speedometer work correctly. The 4-speed used a 17 tooth gear. The car is a dream to drive now. The T-5 shifter is nice and tight compared to the 4-speed shifter and the overdrive is great. It cruises on the highway now at 2600 rpm at 70 mph. Versus 3200 RPM for the 4-speed. I even pushed it up to 80 mph and it will still cruise at that speed no problem. I feel that my daughter can now keep up with traffic without issues. The whole point of this swap for me was lowering the rpm's on the highway. I hope my daughter likes it as she is at work while I did the swap. When I pick her up in it I will have to see if she smiles when She drives it. I know I did.
    85 G.T. All motor
    337 c.i.d 11.44-120 mph

    1984 1/2 G.T. 350 (13.01-106 mph)

    1984 G.T. (Daughters car)

    1986 G.T. (Son's car) (12.99-105 mph)

  15. #15
    FEP Super Member JTurbo's Avatar
    Join Date
    Jan 2006
    Location
    Western MA
    Posts
    6,086

    Default

    Awesome. Glad it was hassle free.
    1979 Indy Pace Car Mustang 302 / 5spd
    1982 Mustang GT T-Top 302 / 4spd
    1986 SVO Mustang - 1C

  16. #16
    FEP Super Member Travis T's Avatar
    Join Date
    Jan 2011
    Location
    China Grove, North Carolina
    Posts
    5,267

    Default

    It's amazing how bolt in it really is. After the swap, my 79 with a two barrel 2.3 and 3.08 gears was knocking down 30 mpg, not to mention with the better first gear it had improved acceleration.
    1984 Mustang GT owned since 1991 (first car). Mercury Mountaineer GT-40P engine, some suspension mods, currently undergoing a five lug SN95 brake upgrade and more suspension mods. Some minor body and interior mods have been done as well.

    2004 GT convertible, 2001 Taurus LX, 1994 F150, 1950 F-1 Ford Pickup

  17. #17
    FEP Power Member 4-barrel Mike's Avatar
    Join Date
    Apr 2010
    Location
    Portland, Oregon
    Posts
    1,953

    Default

    Well done!

    Mike

  18. #18

    Default

    Very late to the party, but I did this swap a week ago. The 4-cyl SROD bellhousing is the same as the 4-cyl T5 bellhousing. Never unclipped the clutch cable, and the original 1979 bellhousing never came off of the car. Just pulled the SROD gearbox out and stabbed the T5 (1991 model) back in its place. The shifter hole even lined up perfectly, same crossmember too. All I had to change was the driveshaft. The entire swap took about 2 hours!! Completely different car now!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •